At present, an OPGW is widely applied in a power system by virtue of its advanced manufacturing technology and higher operational reliability. The OPGW is erected on the same tower with a transmission line, and is positioned at the top of an overhead wire. The OPGW may prevent a lightning and bear a short-circuit current, and is also responsible for transmitting power information. In recent years, since more and more serious natural disasters, severe weather and external damages frequently appear, a rate of occurrence of serious failures of a power grid is increased, chain reactions are easily triggered, and there always exist large-area power outage risks. It is necessary to improve and enhance operation safety and reliability of the OPGW, and particularly, a problem about evaluation of service life of the OPGW which is iced and corroded becomes particularly important. Wherein, torsion resistance of the OPGW is an important performance parameter.
The OPGW mainly consists of an optical unit, a metallic single wire and factice, wherein torsion resistance of the metallic single wire determines a torsion resisting effect of the OPGW. Therefore, a torsional performance test on an OPGW single wire is necessary means for an optical cable product quality supervision and inspection organization and even an optical fiber manufacturer to control product quality.
At present, a method for testing torsional performance of the metallic OPGW single wire is to twist the OPGW single wire in the same direction, and stop testing when it is broken. Its torsional performance is determined through the number of twisting circles when the single wire is broken. This test method is valid for a new OPGW product. However, a practical operation environment of the OPGW single wire is relatively more complex, for example, wind vibration, icing, corrosion and the like, so that, for the torsional performance of the OPGW single wire which works for years or is affected by a disaster, it is difficult to accurately test its practical performance by using the above test method.